Digital painting, based on the original icon attributed to St Luke the Evangelist currently enshrined in the Borghese Chapel of Santa Maria Maggiore.
Admittedly, this reproduction or attempt thereof is not great. Without denying my lack of skill as being in part the cause, this is due to the current condition of the original and the poor quality photos publicly available. Working off what is available was difficult as I could not see the detailed line work. (One would like to think that high-res photography and scanning be utilized for such an important piece of tradition with subsequent public distribution but I guess that might make sense then.)